I just tried to open Softaculous for your account, and now it gave a very clear error:
It appears your account has fully used it’s inode allocation, you will need to delete files to reduce inodes before the script installer will work, or upgrade to premium hosting where we offer over 400,000 inodes !
So it seems that you may have installed a little bit more software than your account can handle. You will need to delete some folders from (unused) scripts on your account to be able to access Softaculous again.